The Coast Guard is asking for the public’s help in locating a missing mariner last seen leaving the Ala Wai harbor about 8 p.m. Thursday.  

Greg Stephanoff, 60, is alone aboard his 42-foot Catalina Sloop, C:Drive, and his destination is unknown.

Stephanoff mentioned to friends wanting to sail to Hanalei Bay on the north shore of Kauai, but he filed no float plan.

The Coast Guard had lifeguards check Hanalei Bay and there was no sign of him, an official in Honolulu said. The Coast Guard also arranged for harbor checks throughout the state and asked flight crews on training missions to keep an eye out, all to no avail.

Stephanoff’s sailboat is white with a gray canvas dodger over the cockpit. Stephanoff is 5 feet 11 inches tall and 160 pounds. He was last seen wearing khaki cargo shorts and a beige aloha shirt.

The Coast Guard is asking all mariners to report any sightings over VHF marine radio channel 16 or to contact the Honolulu Command Center at 842-2600.